package com.xone.xapp;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

public class ImageLoader {
	protected final int TIMEOUT = 5 * 60 * 1000;
	protected MemoryCache memoryCache = new MemoryCache();
	protected FileCache fileCache;
	protected Map<ImageView, String> imageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
	protected ExecutorService executorService;
	protected final int stub_id = R.drawable.loading;
	protected int defaultSize = 70;
	public ImageLoader(Context context) {
		fileCache = new FileCache(context);
		executorService = Executors.newFixedThreadPool(5);
	}
	public ImageLoader(Context context, int defaultSize) {
		fileCache = new FileCache(context);
		this.defaultSize = defaultSize;
		executorService = Executors.newFixedThreadPool(5);
	}
	public Bitmap displayImage(String url, ImageView imageView) {
		imageViews.put(imageView, url);
		Bitmap bitmap = memoryCache.get(url);
		if (bitmap != null) {
			imageView.setImageBitmap(bitmap);
			return bitmap;
		} else {
			queuePhoto(url, imageView);
			imageView.setImageResource(stub_id);
		}
		return null;
	}
	protected void queuePhoto(String url, ImageView imageView) {
		PhotoToLoad p = new PhotoToLoad(url, imageView);
		executorService.submit(new PhotosLoader(p));
	}
	public int getDefaultSize() {
		return defaultSize;
	}
	public void setDefaultSize(int defaultSize) {
		this.defaultSize = defaultSize;
	}
	protected Bitmap getBitmap(String url) {
		File f = fileCache.getFile(url);
		// from SD cache
		Bitmap b = decodeFile(f);
		if (b != null) {
			return b;
		}
		// from web
		try {
			Bitmap bitmap = null;
			URL imageUrl = new URL(url);
			HttpURLConnection conn = (HttpURLConnection) imageUrl.openConnection();
			conn.setConnectTimeout(TIMEOUT);
			conn.setRequestProperty("User-Agent", Constants.USER_AGENT() + Constants.USER_AGENT_TAG);//设置用户的user-agent
			conn.setReadTimeout(TIMEOUT);
			conn.setInstanceFollowRedirects(true);
			InputStream is = conn.getInputStream();
			OutputStream os = new FileOutputStream(f);
			FileUtils.copyStream(is, os);
			os.close();
			bitmap = decodeFile(f);
			return bitmap;
		} catch (Throwable ex) {
			ex.printStackTrace();
			if (ex instanceof OutOfMemoryError) {
				memoryCache.clear();
			}
			return null;
		}
	}
	// decodes image and scales it to reduce memory consumption
	protected Bitmap decodeFile(File f) {
		try {
			// decode image size
			BitmapFactory.Options o = new BitmapFactory.Options();
			o.inJustDecodeBounds = true;
			BitmapFactory.decodeStream(new FileInputStream(f), null, o);
			// Find the correct scale value. It should be the power of 2.
			final int REQUIRED_SIZE = defaultSize;
			int width_tmp = o.outWidth, height_tmp = o.outHeight;
			int scale = 1;
			while (true) {
				if (width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE) {
					break;
				}
				width_tmp /= 2;
				height_tmp /= 2;
				scale *= 2;
			}
			BitmapFactory.Options o2 = new BitmapFactory.Options();// decode with inSampleSize
			o2.inSampleSize = scale;
			return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
		} catch (FileNotFoundException e) {
		}
		return null;
	}
	protected class PhotoToLoad {// Task for the queue
		public String url;
		public ImageView imageView;
		public PhotoToLoad(String u, ImageView i) {
			url = u;
			imageView = i;
		}
	}
	public class PhotosLoader implements Runnable {
		PhotoToLoad photoToLoad;
		PhotosLoader(PhotoToLoad photoToLoad) {
			this.photoToLoad = photoToLoad;
		}
		@Override
		public void run() {
			if (imageViewReused(photoToLoad)) {
				return;
			}
			Bitmap bmp = getBitmap(photoToLoad.url);
			memoryCache.put(photoToLoad.url, bmp);
			if (imageViewReused(photoToLoad)) {
				return;
			}
			BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
			Activity a = (Activity) photoToLoad.imageView.getContext();
			a.runOnUiThread(bd);
		}
	}
	boolean imageViewReused(PhotoToLoad photoToLoad) {
		String tag = imageViews.get(photoToLoad.imageView);
		if (tag == null || !tag.equals(photoToLoad.url)) {
			return true;
		}
		return false;
	}
	protected class BitmapDisplayer implements Runnable {// Used to display bitmap in the UI thread
		protected Bitmap bitmap;
		protected PhotoToLoad photoToLoad;
		public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
			bitmap = b;
			photoToLoad = p;
		}
		public void run() {
			if (imageViewReused(photoToLoad)) {
				return;
			}
			if (bitmap != null) {
				photoToLoad.imageView.setImageBitmap(bitmap);
			} else {
				photoToLoad.imageView.setImageResource(stub_id);
			}
		}
	}
	public void clearCache() {
		memoryCache.clear();
		fileCache.clear();
	}
}
